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[PATCH] uprobes: Fix utask->depth accounting in handle_trampoline()
- From: Oleg Nesterov <oleg at redhat dot com>
- To: Ingo Molnar <mingo at elte dot hu>
- Cc: anton at redhat dot com, Hemant Kumar Shaw <hkshaw at linux dot vnet dot ibm dot com>, masami dot hiramatsu dot pt at hitachi dot com, Mikhail Kulemin <Mikhail dot Kulemin at ru dot ibm dot com>, srikar at linux dot vnet dot ibm dot com, systemtap at sourceware dot org, linux-kernel at vger dot kernel dot org
- Date: Wed, 11 Sep 2013 17:47:26 +0200
- Subject: [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline()
- Authentication-results: sourceware.org; auth=none
Currently utask->depth is simply the number of allocated/pending
return_instance's in uprobe_task->return_instances list.
handle_trampoline() should decrement this counter every time we
handle/free an instance, but due to typo it does this only if
->chained == T. This means that in the likely case this counter
is never decremented and the probed task can't report more than
MAX_URETPROBE_DEPTH events.
Cc: stable@vger.kernel.org
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Mikhail Kulemin <Mikhail.Kulemin@ru.ibm.com>
Reported-by: Hemant Kumar Shaw <hkshaw@linux.vnet.ibm.com>
---
kernel/events/uprobes.c | 4 +---
1 files changed, 1 insertions(+), 3 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f356974..ad8e1bd 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1682,12 +1682,10 @@ static bool handle_trampoline(struct pt_regs *regs)
tmp = ri;
ri = ri->next;
kfree(tmp);
+ utask->depth--;
if (!chained)
break;
-
- utask->depth--;
-
BUG_ON(!ri);
}
--
1.5.5.1